The invention relates generally to an inlet of an aircraft engine and, more particularly, to a system and method for actively changing an effective flow-though area of the inlet, to vary the Mach number of airflow through the inlet.
The amount of noise that is generated by an aircraft engine during the takeoff and landing of an aircraft continues to be a concern and is often limited by government regulation. Sources of noise for aircraft engines include fan and inlet noise. Accordingly, it would be desirable to develop a system and a method for reducing fan and inlet noise during takeoff and landing operations. It would further be desirable for the system and method to avoid reducing performance characteristics of the aircraft engine during the remainder of the flight.
Briefly, in accordance with one embodiment of the present invention, an active effective flow-though area control system includes an upstream wall-flow perturber and a downstream wall-flow perturber situated in an inlet region of an aircraft engine. The downstream wall-flow peturber is positioned downstream from the upstream wal-flow perturber. The upstream and downstream wall-flow peturbers are configured to generate and trap at lease one region of separated, vortical flow in the airflow through the inlet region.
For another embodiment of the invention, a variable effective flow-through area inlet of an aircraft engine is disclosed. The variable effective flow-through area inlet includes an inner wall defining an airflow passage and an upstream and a downstream wall-flow perturber connected to the inner wall. The upstream and downstream wall-flow perturbers are configured to generate and trap at least one region of separated, vortical flow in the airflow within the airflow passage.
A method embodiment, for actively changing an effective flow-through area of an inlet region of an aircraft engine, is also disclosed. The method includes creating at least one region of separated, vortical flow in an airflow passage defined by the inlet region. The method further includes trapping the region of separated, vortical flow in the airflow passage. The region of separated, vortical flow partially obstructs a main inlet airflow.